Dusky spinefoot (Siganus luridus)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Teleostei · Order: Acanthuriformes · Family: Siganidae · Genus: Siganus.

Accepted name: Siganus luridus · Authority: (Rüppell, 1829) · Taxonomic status: accepted · AphiaID: 127044.

Synonyms and superseded combinations recorded for this taxon: Amphacanthus abhortani Valenciennes, 1835; Amphacanthus luridus Rüppell, 1829; Teuthis lurida (Rüppell, 1829).

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127044 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (FishBase)

Measured values published by FishBase for Siganus luridus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 30 cm · Common length: 20 cm · Depth range: 2–40 m · Habitat zone: reef-associated · Body shape: fusiform / normal · Vulnerability index: 39.4 of 100 · Fishery importance: minor commercial · Aquarium trade: never/rarely.

FishBase notes: Found in small schools in very shallow water close to the bottom. Prefer hard bottoms of compacted sand with rock or coral debris. Solitary adults and groups of 3 or 4 adults have also been observed. Feed on a wide range of benthic algae. May suddenly stop and erect its fins (dorsal, anal and pelvic) presenting an encircling array of spines to potential predators; these spines are venomous. A food fish that is occasionally poisonous (Ref. 4537). Probably does not adapt well in captivity (Ref. 12382). A thermophilic species (Ref. 120766). Minimum depth from Ref. 9710.

Source: FishBase species summary (SpecCode 4613) — https://www.fishbase.se/summary/Siganus-luridus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

7,699 georeferenced occurrence records for Siganus luridus are published through GBIF from 33 countries or marine areas. The map above plots 95 distinct locations from a sample of 3,000 records, omitting 49 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Greece (3,566); Malta (1,274); Italy (738); Croatia (619); Spain (278).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 2390262) — https://www.gbif.org/occurrence/search?taxon_key=2390262&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=127044 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Conservation status (IUCN Red List)

The IUCN Red List assesses Siganus luridus (Rüppell, 1829) as Least Concern (code LC). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.

Source: IUCN Red List of Threatened Species (taxon 18178550) — https://www.iucnredlist.org/species/18178550/0; GBIF IUCN Red List category endpoint (taxonKey 2390262) — https://api.gbif.org/v1/species/2390262/iucnRedListCategory. Accessed 2026-09-23.

Description and natural history (Wikipedia)

The dusky spinefoot was first formally described in 1829 as Amphacanthus luridus by the German naturalist and explorer Eduard Rüppell with the type locality given as the Red Sea. The specific name luridus means "pale yellow", this name was given to it by the collector of the type specimen, Christian Gottfried Ehrenberg, According to Achille Valenciennes in 1835, Ehrenberg described the colour of the body as yellowish-brown, with numerous very thin pale yellow lines. However, Rüppell said that the colour was bluish black with some irregular, paler spots and a yellowish ring around pupil in his description.

The dusky spinefoot has a compressed body which Has a depth which fits into its standard length 2.1 to 2.8 times. There is a single row of incisor-like teeth in the jaws, each with 1 or 2 lateral cusps. The dorsal fin contains 13-14 spines and 10 soft rays while the anal fin has 7 spines and 9 soft rays. The caudal fin is truncate. This species attains a maximum total length of 30 cm, although 20 cm is more typical. The colour is variable, it is normally olive green to dark brown with a mottled pattern.

The dusky spinefoot is found on the coast of eastern Africa from Mozambique northwards into the Red Sea, and also the Comoros, Madagascar, and the Mascarene Islands. Its presence in the Persian Gulf needs to be confirmed. Recorded first in the Mediterranean Sea in 1955 off Israel, following entry via the Suez Canal, it fast expanded across the eastern Basin and now reaches westwards as far as the French Mediterranean coast and the Adriatic Sea.

It is found at depths between 2 and 40 m in waters over hard substrates, such as coral and rocky reefs.

The dusky spinefoot spawns in April and from June to August when the seawater temperature is between 24 and 29 C, the eggs and larvae are planktonic. The larvae stay close to the surface where they feed on phytoplankton and zooplankton from 3 days old. The adults are herbivores which are active during the day, hiding in cavities during the hours of darkness. They are frequently encountered in schools but solitary individuals can also be seen, grazing on algae from the substrate. It feeds on larger brown algae species, as well as other macrophytes.

This species produces venom in the spines of its fins. In a study of the venom of a congener it was found that rabbitfish venom was similar to the venom of stonefishes. This species has been observed stopping suddenly. erecting the dorsal, anal and pelvic to present a potential threat with an array of venomous spines around its body.

The venomous spines are used for defence against predators so the highest predation pressure is on the planktonic and larval stages. Known parasites of the dusky spinefoot included the monogenean Glyphidohaptor plectocirra and Tetrancistrum polymorphum as well as the digeneans Hexangium brayi, Hexangium sigani and Progyliauchen magnacetabulum.

The dusky spinefoot is caught using set fish traps, gillnets and beach seines, the catch is sold as fresh fish. This species has become an important species for fisheries in the Mediterranean while in other areas, such as Kenya, it is a bycatch. This species has been implicated in cases of mild ciguatera like poisoning when consumed.

Source: Wikipedia: Dusky spinefoot — https://en.wikipedia.org/wiki/Dusky_spinefoot (CC BY-SA 4.0). Accessed 2026-09-23.